Page 76 - Application Handbook - Liquid Chromatography

LAAN-A-LC-E258

Application High Performance Liquid Chromatography

News Analysis of Sugars and Sugar Alcohols in Energy

Drink by Prominence-i with Differential Refractive
No.L481 Index Detector

Sugars and sugar alcohols display almost no ultraviolet
absorption, and are therefore typically detected using a
differential refractive index detector or evaporative light uRI
scattering detector. By using a ligand exchange column for 80 n Peaks
sugar analysis, it is possible to distinguish among the different 1. maltose
isomers based on the position of the hydroxyl group in the 70 1 2. glucose
chair conformation of glucose and fructose for example. In 4 3. fructose
4. erythritol
other words, the hydroxyl group of the sugar and the metal 60 5 5. mannitol
ion of the stationary phase form a complex, making it 2 3 6. sorbitol
possible to achieve separation due to the difference in the 50 6
strength of the complex formation. Also, maintaining a 40
column temperature of 80 °C suppresses sugar anomer
separation and peak dispersion, thereby achieving good 30
separation of adjacent peaks.
The new Prominence-i integrated high-performance liquid 20
chromatograph can be connected to the RID-20A differential
refractive index detector. The column oven, which can 10
accommodate a 30 cm column and maintain temperature
control up to 85 °C, therefore supports applications that 0
require a long column.
In Application News No. 467, we introduced an example of 0 5 10 15 20 25 min
analysis of sugars in juice, in which the Prominence-i was
connected to a differential refractive index detector. Here, we
introduce an example of simultaneous analysis of sugars and Fig. 1 Chromatogram of a Standard Mixture of Six Sugars
sugar alcohols in an energy drink using the Prominence-i and (10 g/L each, 10 µL Injected)
RID-20A.
n Analysis of a Standard Mixture of Six Sugars
Sorbitol, xylitol, mannitol and erythritol are a type of sugar
alcohol that because of their relative sweetness, are used as uRI
80
sweeteners. When conducting simultaneous analysis of sugars n Peaks
and sugar alcohols, a hydrophilic compound analytical column, 70 1. maltose
such as the SPR-Ca or SPR-Pb, is suitable along with the use of 2. glucose
a combination of the size exclusion and ligand exchange 60 1 2 3. fructose
modes of analysis. Fig. 1 shows the results of analysis of a 4. mannitol
5. xylitol
standard solution of six sugar alcohol substances (10 g/L each 50 3 6. sorbitol
of maltose, glucose, fructose, erythritol, mannitol and sorbitol)
using the SPR-Ca column with a 10 µL injection. The analytical 40 4
conditions are shown in Table 1. 5
Fig. 2 shows the results of analysis of a standard solution of six 30 6
sugar substances including sugar alcohols (10 g/L each of
maltose, glucose, fructose, mannitol, xylitol, sorbitol) using a 20
10 µL injection, and Table 2 shows the analytical conditions
that were used. The SPR-Pb was used as the analytical column. 10
Table 1 Analytical Conditions 0
Column : Shim-pack SPR-Ca (250 mm L × 7.8 mm I.D., 8 µm)
Mobile Phase : Water
Flowrate : 0.6 mL/min 0 10 20 30 40 min
Column Temp. : 80 °C
Injection Volume : 10 µL
Detection : RID-20A
Polarity +, Cell temp. 40 °C, Response 1.5 sec Fig. 2 Chromatogram of a Standard Mixture of Six Sugars
(10 g/L each, 10 µL Injected)
Table 2 Analytical Conditions
Column : Shim-pack SPR-Pb (250 mm L × 7.8 mm I.D., 8 µm)
Mobile Phase : Water
Flowrate : 0.6 mL/min
Column Temp. : 80 °C
Injection Volume : 10 µL
Detection : RID-20A
Polarity +, Cell temp. 40 °C, Response 1.5 sec